Glucosinolate Profiling and Antimicrobial Screening of Aurinia leucadea (Brassicaceae)

Abstract

Glucosinolates (GLs) were characterized in various aerial parts (stems, leaves, and flowers) of Aurinia leucadea (Guss.) C. Koch and quantified according to the ISO 9167-1 official method based on the HPLC analysis of desulfoglucosinolates. Eight GLs, i.e., glucoraphanin (GRA), glucoalyssin (GAL; 1), gluconapin (GNA; 2), glucocochlearin (GCC), glucobrassicanapin (GBN; 3), glucotropaeolin (GTL), glucoerucin (GER), and glucoberteroin (GBE) were identified. The total GL contents were 57.1, 37.8, and 81.3 μmol/g dry weight in the stems, leaves, and flowers, respectively. The major GL detected in all parts of the plant was 2, followed by 1 and 3. GC/MS Analysis of the volatile fractions extracted from the aerial parts of fresh plant material either by hydrodistillation or CH(2) Cl(2) extraction showed that these fractions mostly contained isothiocyanates (ITCs). The main ITCs were but-3-enyl- (55.6-71.8%), pent-4-enyl- (7.6-15.3%), and 5-(methylsulfinyl)pentyl ITC (0-9.5%), originating from the corresponding GLs 2, 3, and 1, respectively. The antimicrobial activity of the volatile samples was investigated by determining inhibition zones with the disk-diffusion method and minimal inhibitory concentrations (MIC) with the microdilution method. They were found to inhibit a wide range of bacteria and fungi, with MIC values of 2.0-32.0 μg/ml, indicating their promising antimicrobial potential, especially against the fungi Candida albicans and Rhizopus stolonifer as well as against the clinically important pathogen Pseudomonas aeruginosa.

Glucosinolates profile, volatile constituents, antimicrobial, and cytotoxic activities of Lobularia libyca

“…A sterilized filter paper disc saturated with 1 mg of sample or standard was placed on a plate containing solid bacterial medium (nutrient agar broth) or fungal medium (Dox's medium) inoculated with the tested organism. After incubation, the diameter of the clear zone of inhibition was taken as a measure of the inhibitory power of the sample against the particular test organism (Blazevic et al 2011). …”

“…The activity of the seed hydrolysate on P. aeruginosa and S. aureus may be due to the presence of iberin in the extract which shows the highest antibacterial efficacy index on these two organisms (Wilson et al 2013). Blazevic et al (2011) tested the volatile samples obtained from Aurinia leucadea and found that they have a potent antibacterial and antifungal activities, especially against P. aeruginosa and C. albicans. Another species Aurinia sinuate has a great activity on the same micro-organisms (Mastelic et al 2010).…”

Glucosinolate Profile of Croatian Stenoendemic Plant Fibigia triquetra (DC.) Boiss. ex Prantl.

“…[11][12][13][14] Our group has previously focused on the GL profile of endemic plants of the tribe Alysseae, which comprises seven genera: Alyssoides, Alyssum, Aurinia, Berteroa, Clypeola, Degenia and Fibigia. Those investigations [8,15,16,31,33] of, namely, D. velebitica, Aurinia sinuata (L.) Griseb. and A. leucadea (Guss.)…”

“…[15] Plant samples were reduced to a fine powder. Samples of ca 500 mg were extracted for 5 min at 80 °C in 2  5 mL EtOH-H2O (70 : 30 v / v), homogenized and then centrifuged.…”

“…However, the nature of GLs and their relative amounts can vary greatly with plant species and variety, tissue type (seed, root, stem, leaf, flower) and developmental stage of the tissue. [8,15,16] Thus, the aim of the present study was to investigate the qualitative and quantitative GL profile in the various aerial parts (flower, leaf, stem, seed) of F. triquetra. The identification and quantification were performed by HPLC-DAD of the desulfo-glucosinolates (DS-GLs) and comparison with standards.…”